Heater for transformer oil



July' 5,1927. 1,634,719

' D. G. MOARN HEATER FOR TRANSFQRMER OIL Filed March 25, 1926 not congeal, which might Patented July 5, 1927.,

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mum GBA'I'IAN"ncaRm or'PI'r'rsBURGH, rEnNsYnvANIA, Assitnton rorrr'rs- *BUIGE 'I'RLIQIICIRMIIIR COMPANY, A CORPORATION (BF-PENNSYLVANIA.

rmaaanron Tmsmmm OIL.

I Applicationjflled March 23,1926. Serial No. 96,823.

transformer Oll.

Transformers of the herein disclosed 5 are'usiially' provided w1 an exterior oil expansion tank having communication with the transformer casing by suitable piping. It is necessar for proper operation of the transformer t at the oil in the piping shall happen dnring cold weather. 4

It is an object of my invention to provide an improved heater to prevent congealing of the oil. A further object is to provide an improved electrical heater which is simple in construction and adapted if desired, as a standard product, to be applied to any standard installation. Another object is to provide an electrical heater so arranged that there will not be set up any magnetic fluxin the piping, thereby preventing the generation of electric current in the piping.

In a more specific aspect of the'invention, an object is to wind thev heating coil in a noninductive manner so that the magnetic flux present in the coil itself will be automatically neutralized. other objects will appear in the following description of the accompanyin drawings, in which %ig. 1 is a fra with my improved heater applied thereto, and i I Fig. 2 is an enlarged sectional view of the so heater. y 'In the illustrative embodiment of my invention 'I have shown a transformer casing.v

I The heater comprises a piece of tubing 9' having flanged ends 10 and 11, in turn having axial flanges 12. A coil 13 wound upon the tubing 9 between the flanges lO and 11 is surrounded by several layers of insulat in material 14 preferably asbestos 9. er. whole coil iii sealed by an outer entary partially sectional view of a trans ormer and expansion tank cal" cover pofrtionl5having'ends 16 which are either bent under the flanges 12 or welded thereto. The jcoil'lead wires 17 extend out through a suitable insulator support- 18 and current to the coil may be supplied in any suitable manner, such forinstance as from the a transformer current.

The coil'is wound non-inductively preferably by bending the wire back on itself approximately at the center thereof, then attaching the center of the wire to one, end of the tube 9 and winding both portions of the wire side by side or parallel in the same direction and in layers. By such a winding there are no complete turns around the pipe, i. e., the current in one wire will neutralize the current in the other wire, thereby preventing any magnetic flux or current from flowing in the piping. This eliminates any danger from fire which might otherwise be caused by electric current or magnetic flux in the pipe and tank.

If the coil is supplied with current from a high powered source, such as from the transformer, the character of the coil Wire will be governed accordingly so as to offer the proper resistance for the desired heat to b generated.

I claim 1. The combination with a transformer casing and an oil expansion'tank therefor having a piping connection therewith, of a self-contained heater comprising an electrical winding anda casing entirely enclosing the same, said casing having a longitudinal bore within which a portion of said piping is snugly disposed and adapted to be slid relative thereto.

2. The combination with a transformer casing and an oil expansion tank therefor having a piping connection therewith, of'a heater having an opening for slidably receiv I ing a portion of said piping, and said heater comprising a non-inductively wound electrical heating coil. 3. A transformer oil heater comprising a supporting member for receiving an oil pipe, and a heating coil non-inductively wound on said support. 2 j 4. A transformer oil heater comprising a tubular member for receiving an oil pipe, and a non-inductive heating coil wound upon said tube. v

5. A self contained transformer oil heater comprising a tube for receiving an oil pipe and baring; flanged ends, a heating coil disposed around said tube and between said ends. and a cover member enclosing said coil by being secured to said flanged ends.

U. A sel't'contained transformer oil heater comprising a tube for receiving an oil pipe and having flanged ends, a heating coil disposed around said tube and between said ends, a cover member enclosing said coil by being Secured to said flanged ends, and an insulatine member interposed between said cover and the outer portion of said coil.

7. A self-contained transformer oil heater comprising a tube for receiving an oil pipe layers of asbestos paper Wound upon the exterior of said ('oil and within said cover. 8. A transfoi'iner oil heater comprising a tube adapted to receive an oil. pipe and a heating coil wound upon said tube, said coil consisting of a wire bent upon itself with the bent end attached to said tube, While the Wire with its parallel portions extends around the tube in the same direction.

DONALD GRATTAN Moi KEN. 

